Try to browse to the backup directory of jv16 PowerTools and using the Right Click menu try to restore the registry backup files (files called entries.reg).
If this doesn't work the only way is to restore the system using a System Restore or install Windows over the current installation. Installing Windows over without formating you shouldn't lose any of your files or other data.
If you do this, please send me the backup file(s) for further analysis so I could say what caused the problem.